Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L69/00—Compositions of polycarbonates; Compositions of derivatives of polycarbonates

Definitions

• the invention relates to a thermoplastic molding composition made from an aromatic polycarbonate, a graft copolymer based on ABS, the shell of which is constructed in two stages, and a thermoplastic copolymer.
• the PC / ABS mixtures known from (1) and (2) are generally distinguished by good mechanical properties, in particular good axial and multiaxial toughness down to low temperatures and high Vicat temperatures.
• the main areas of application are the motor vehicle sector and the electrical and household appliance industry.
• the requirements for the materials include high toughness - even at low temperatures - easy processing - especially with workpieces of complex shapes - as well as excellent surface properties.
• the molding compositions known from (3) and (4) have good toughness, but still have unsatisfactory flow properties.
• the object was therefore to propose mixtures of graft copolymers based on ABS with PC which have good toughness and improved flowability.
• This problem is solved - generally speaking - with a molding compound made from mixtures with graft rubbers based on conjugated dienes with a double-shell shell made of an acrylate with 2 to 8 carbon atoms and vinyl aromatic monomers and ethylenically unsaturated comonomers.
• Such molding compositions have a significantly better flow property with comparable toughness than those with known graft rubbers.
• the molding composition according to the invention contains, for example, the following proportions of the components (in% by weight, in each case based on the molding composition from A, B and C): Component A: 20 to 85, especially 30 to 70; Component B: 5 to 50, in particular 10 to 35; Component C: 5 to 70, in particular 10 to 40.
• the molding composition from A, B and C can also contain 0.1 to 40 parts by weight, preferably 0.4 to 35 parts by weight of conventional additives (component D) and can also be mixed are, for example, with 5 to 60, preferably 7 to 40 parts by weight, based in each case on A + B + C, of a molding composition in the form of a further graft copolymer based on ABS (component E).
• component D conventional additives
• component E graft copolymer based on ABS
• Thermoplastic, aromatic polycarbonates A suitable according to the invention are those based on the diphenols (bisphenols) of the formula (I) wherein Y is a single bond, C1-C5-alkylene, C2-C5-alkylidene, C5-C6-cycloalkylidene, -S- or -SO2-, chlorine, bromine or methyl and m is zero or one and n is zero, one or two.
• Polycarbonates according to component A which are suitable according to the invention are both homopolycarbonates and copolycarbonates.
• the diphenols of the formula (I) are either known or can be prepared by known processes.
• the preparation of the polycarbonates according to component A which are suitable according to the invention is known and can be carried out, for example, by the interfacial process or by the homogeneous phase process (the so-called pyridine process), the molecular weight to be set in each case being achieved in a known manner by a corresponding amount of known chain terminators (with respect polydiorganosiloxane-containing polycarbonates, see for example DE-OS 33 34 782).
• Suitable chain terminators are, for example, phenol, p-chlorophenol, p-tert-butylphenol or 2,4,6-tribromophenol, but also long-chain alkylphenols such as 4- (1,3-tetramethylbutyl) phenol, according to DE-A-2 842 005 or monoalkylphenols or dialkylphenols with a total of 8 to 20 carbon atoms in the alkyl substituents according to DE-AP 35 06 472 such as p-nonylphenyl, 3,5-di-tert-butylphenol, p-tert.-octylphenol, p- Dodecylphenol, 2- (3,5-dimethylheptyl) phenol and 4- (3,5-dimethylheptyl) phenol.
• long-chain alkylphenols such as 4- (1,3-tetramethylbutyl) phenol, according to DE-A-2 842 005 or monoalkylphenols or dialky
• the polycarbonates according to component A which are suitable according to the invention have average weight-average molecular weights (Mw, measured for example by ultracentrifugation or scattered light measurement) from 10,000 to 200,000, preferably from 20,000 to 80,000. This corresponds to relative viscosities ⁇ rel from 0.8 to 2.4 (ml / g), in particular from 1.1 to 1.6 ( ml / g).
• Suitable diphenols of the formula (I) are, for example, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2-bis (4-hydroxyphenyl) propane, 2,4-bis (4-hydroxyphenyl) -2-methylbutane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) - propane and 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane.
• Preferred diphenols of the formula (I) are 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane, 2,2-bis (3 , 5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) cyclohexane.
• polycarbonates according to component A which are suitable according to the invention can be branched in a known manner, preferably by incorporating 0.05 to 2.0 mol%, based on the sum of the diphenols used, of three- or more than three-functional compounds, for example those with three or more than three phenolic OH groups.
• preferred polycarbonates are the copolycarbonates of bisphenol A with up to 15 mol%, based on the molar sum of diphenols, of 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane.
• the polycarbonates can also be replaced in whole or in part by polyester carbonates (copolymers which contain both esters and carbonate structures).
• the graft copolymer B used is an emulsion graft copolymer which has a two-stage hard phase as the graft shell and an elastomer phase b 1) as the graft base.
• the elastomer phase b 1) is a homopolymer or copolymer which is composed essentially of an aliphatic diene with 4 to 5 C atoms or in addition to this (s) at least one monomer of an acrylic acid alkyl ester with 1 to 8 C atoms in the alkyl radical or styrene or may contain acrylonitrile.
• the elastomer phase serving as the graft base for the graft copolymer B has an average particle size in the range from 0.05 to 0.7 ⁇ m (d50 value of the integral mass distribution), preferably from 0.1 to 0.45 ⁇ m. It can be monomodal or bimodal, i.e. have a proportion of particles in the range from 0.05 to 0.18 ⁇ m and another in the range from 0.25 to 0.5 ⁇ m, e.g. in US 4,430,478.
• the graft copolymer has a further shell b3) which, based on B, makes up 20 to 50% by weight, preferably 30 to 50% by weight.
• Suitable monomers b3a2) are in particular (meth) acrylonitrile or methyl methacrylate or mixtures of these monomers. AN is preferred. Styrene is preferably used as the vinyl aromatic monomer b3a1. However, styrene mixed with ⁇ -methylstyrene or p-methylstyrene can also be used if more heat-resistant products are desired, but this is not preferred. To produce molding compositions with high heat resistance, (meth) acrylonitrile or MMA can be replaced in whole or in part by maleic anhydride or N-substituted maleimides.
• the graft copolymer is prepared on the basis of the graft base produced in the emulsion, so that the monomers are first added to the first shell and applied in an emulsion in a known manner.
• the second graft shell is then polymerized onto this elastomer, which is essentially grafted with acrylates.
• the grafting in both process stages is carried out in such a way that the monomer mixture (the monomer) of the monomers forming the graft is added to the aqueous emulsion of the respective graft base in the weight ratio mentioned above. If necessary, further emulsifiers can be added during the grafting.
• the polymerization is triggered by free radical initiators such as azo compounds or peroxides.
• the polymerization temperature can be between 30 and 100 ° C.
• Conventional auxiliaries such as regulators and stabilizers can be present for the implementation of the polymerization.
• the copolymer C is composed of monomers that form a hard phase. It can be done in the usual way by polymerizing a vinyl aromatic monomer C1 with 8 to 12 carbon atoms, MMA or mixtures thereof in proportions of 95 to 50% by weight, in particular 80 to 65% by weight, in a mixture with an ethylenically unsaturated monomer C2 in Proportions of 50 to 5, in particular from 35 to 20 wt.% Are produced.
• Suitable vinyl aromatic monomers C1 are styrene and the alkylstyrenes, in particular the ⁇ -methylstyrene or the p-methylstyrene.
• ⁇ -Methylstyrene is mainly used when high heat resistance of the molding materials is to be achieved. Mixtures of styrene and acrylonitrile with up to 30% by weight of ⁇ -methylstyrene are usually used for this purpose. Suitable ethylenically unsaturated monomers are (meth) acrylonitrile, MMA, maleic anhydride, N-substituted maleimides or mixtures thereof. Copolymers containing 20 to 35% by weight of acrylonitrile and 80 to 65% by weight of styrene are preferably used.
• the group C2 (meth) acrylonitrile or MMA entirely or partially replaced by maleic anhydride or N-substituted maleimides.
• These copolymers are commercially available and can be prepared, for example, according to the teaching of DE-AS 10 01 001 or according to the teaching of DE-PS 10 03 436.
• the molecular weight range of the copolymer is 80,000 to 250,000 (weight average M w from light scattering. This corresponds to viscosity numbers, VZ, of 35 to 130 (ml / g), in particular 50 to 100 (ml / g).
• the molding composition according to the invention can contain, as component C, additives which are typical and customary for polycarbonates, SAN polymers and graft copolymers based on ABS etc. or mixtures thereof.
• additives are: fillers - in particular glass and carbon fibers - and materials for increasing the shielding from electromagnetic waves (e.g. metal flakes, powders, fibers, metal-coated fillers), dyes, pigments, antistatic agents, antioxidants, stabilizers, too Flame retardants and in particular the lubricants used for the further processing of the molding compound, for example are required in the production of moldings or moldings.
• lubricants especially those based on N, N'-bisstearylethylenediamine (Accrawachs) are to be mentioned, which are preferably used to keep the processing properties of the molding compositions at a high level. Surprisingly, these are more suitable than silicone oils, Pluriole® and the stearates.
• the molding composition may also contain blowing agents for the production of foamed parts (e.g. azodicarbonamide).
• blowing agents for the production of foamed parts e.g. azodicarbonamide.
• the flame retardants can be halogen, preferably bromine-containing low and high molecular weight (aromatic) compounds selected from the classes of aryls, aryl ethers, aryl alkyl ethers, aryl amines, aryl imides, aryl anhydrides, phenols, aryl alkyl imides and aryl siloxanes.
• aromatic preferably bromine-containing low and high molecular weight (aromatic) compounds selected from the classes of aryls, aryl ethers, aryl alkyl ethers, aryl amines, aryl imides, aryl anhydrides, phenols, aryl alkyl imides and aryl siloxanes.
• Aryls hexabromobenzene, brominated oligomeric styrene (BOS), pentabromomethylbenzene
• Aryl ethers decabromodiphenyl ether, octabromodiphenyl ether, poly (2,6-dibromo-1,4-phenylene) ether
• Aryl alkyl ethers bis (2,4,6-tribromophenoxy) ethane, bis (pentabromophenoxy) ethane, poly (tetrabromobisphenol-A-glycidyl) ether, poly (tetrabromohydroquinone-1,2-ethylidene) ether
• Arylamines tris (2,4-dibromophenyl) amine, bis (pentabromphenyl) amine; Tribromaniline;
• Aryl anhydrides tetrabromophthalic anhydride;
• Aryl anhydrides tetrab
• halogen-containing flame retardants are preferably used together with synergists such as antimony, bismuth and phosphorus compounds.
• halogen-free flame retardants especially organic phosphorus compounds in combination with small amounts of highly fluorinated polymers (e.g. PTFE) can also be used.
• Octabromodiphenyl ether Preferably used: Octabromodiphenyl ether, DE 79® from Great Lakes, poly (2,6-dibromo-1,4-phenylene) ether, PO 64 P® from Great Lakes, poly (tetrabromobisphenol-A-glycidyl) ether, F 2400® from Makhteshim, ethylene bis (tetrabromophthalimide), Saytex BT 93® from Saytech and bis (2,4,6-tribromophenoxy) ethane, Firemaster FF 680® from Great Lakes.
• poly- or oligo (tetrabromobisphenol A) carbonate BC 52® from Great Lakes and poly (tetrabromobisphenol-A-glycidyl) ether (F 2400 from Makhteshim) or partially halogenated polycarbonates (copolymers).
• the molding composition according to the invention can additionally contain a further graft copolymer based on ABS, which, in contrast to B, has a coarse particle size and is produced in bulk, solution or bulk suspension can. This is preferably done in solution.
• the production is known and is sufficiently described, for example, in US Pat. No. 4,430,470.
• the graft copolymer and the hard phase of E are prepared simultaneously in one step, a grafting yield of 5 to 30%, preferably 5 to 20%, being set.
• Graft yield is understood to mean the weight ratio of the graft monomers actually grafted on to the graft monomers x 100 used overall.
• the vinyl aromatic monomers are the same as those used in the production of B. Preferably only styrene is used together with acrylonitrile. Examples of solvents are in question cyclohexane or alkyl aromatics, especially ethylbenzene.
• the preferred elastomer is polybutadiene with cis contents of 30 to 40% and 1,2-vinyl contents of 7 to 14%. Copolymers of butadiene with 15 to 40% by weight of vinyl aromatic monomers, in particular styrene, can also be used. Mixtures of polybutadiene and styrene-butadiene block rubbers can also be used. A preferred procedure for the preparation of the graft copolymer is described in DE-OS 14 95 089.
• composition of the graft cover of E can differ from that of B.
• copolymers C and the hard phase of E can be the same or different and can also differ from the graft shells.
• Components A, B, C and optionally D and E can be mixed by all known methods. However, components A, B, C and, if appropriate, D and E are preferably mixed at temperatures from 200 to 320 ° C. by extruding, kneading or rolling the components together, the components, if necessary, beforehand from the solution obtained in the polymerization or from the aqueous dispersion have been isolated.
• the products of the graft copolymerization (component B) obtained in aqueous dispersion can, however, also be partially dewatered or mixed directly with component C as a dispersion.
• the graft copolymers B are completely dried during the mixing. However, it is also possible to mix the partially dewatered component B or its dispersion directly with C, the polycarbonate A and the components D and E, the complete drying of B then taking place during the mixing.
• the molding composition according to the invention can be processed by the known methods of thermoplastic processing, e.g. by extrusion, injection molding, calendering, blow molding, pressing or sintering. Shaped parts for automobile construction are preferably produced from the molding compositions produced by the process according to the invention by injection molding.
• a commercially available polycarbonate based on bisphenol A with a relative solution viscosity ⁇ rel of 1.30 ml / g was used as component A.
• a polybutadiene latex was obtained, the average particle size of which is 0.1 ⁇ m.
• This latex is agglomerated by adding 25 parts of an emulsion of a copolymer of 96 parts of ethyl acrylate and 4 parts of acrylic acid amide with a solids content of 10% by weight, a polybutadiene latex having an average particle size of 0.3 to 0.4 ⁇ m being formed.
• the agglomerated polymer latex was diluted with water, so that after the polymerization of the graft monomers of the 1st graft shell was complete, the solids content was 40% by weight. After adding, each based on b2, 0.75% emulsifier, 0.5% dodecyl mercaptan and 0.3% potassium peroxodisulfate, 5% of a mixture of n-butyl acrylate and dihydrodicyclopentadienyl acrylate in a weight ratio of 98: 2 was slowly added. The polymerization was carried out while stirring the mixture at 65 ° C. The turnover, based on b2, was practically quantitative.
• the procedure was as in the production of graft rubber 1, but 20% by weight of a mixture of ethylhexyl acrylate and allymethacrylate in a weight ratio of 99.5 to 0.5 were used and grafted to build up the first shell b2).
• polybutadiene latex b 1 140 parts by weight of polybutadiene latex b 1 were mixed with 34 parts of a mixture of styrene and acrylonitrile (ratio 76:24) and 50 parts of water and with stirring after the addition of a further 0.08 part of potassium persulfate and 0.05 part of lauroyl peroxide for 65 hours ° C heated. The product was then precipitated from the dispersion using calcium chloride solution at 95 ° C., washed with water and dried in a warm air stream.
• graft rubber 4 Like graft rubber 4, but instead of 34 parts of the mixture of styrene and acrylonitrile, 28 parts of a mixture of styrene, acrylonitrile and n-butyl acrylate in a weight ratio of 52:22:26 were grafted onto b1.
• the product was precipitated from the dispersion using calcium chloride solution at 95 ° C., washed with water and dried in a warm air stream.
• the graft polymer obtained was worked up in each case as described under graft polymer 1.
• DI A symmetrical three-block copolymer XYX, composed of 10% by weight of ethylene oxide and 90% by weight of propylene oxide, with the molecular weight 2800 of the middle block was used as the lubricant.
• DII N, N′-bisstearylethylenediamine (Accrawachs) was used as a further lubricant.
• Polybutadiene is dissolved in a mixture of styrene, acrylonitrile and ethylbenzene.
• the styrene / acrylonitrile ratio is 75/25% by weight.
• the mixture is polymerized with vigorous stirring in a continuous process in three reactors arranged in series with increasing temperature profiles.
• part of the styrene / acrylonitrile mixture polymerizes onto the polybutadiene and forms the graft polymer, while the remainder forms a copolymer (hard matrix).
• the polymerization product was degassed, extruded and then granulated.
• the following analysis data were found: 9.3% polybutadiene, 68% polystyrene, 22.7% acrylonitrile.
• the graft yield is 8.5%.
• the mean diameter determined by counting the particles on the electron micrographs is 1.4 ⁇ m.
• the product receives 17% of a coarse graft rubber and 83% of a copolymer with a VZ of 84 ml / g.
• the shell structure of the graft rubbers according to the invention leads to molding compositions with improved flowability and, at the same time, good toughness compared to the comparison compositions.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6346702

Family Applications (1)

Country Status (2)

Cited By (4)

Citations (6)

• 1988
  • 1988-02-05 DE DE19883803458 patent/DE3803458A1/de not_active Withdrawn
• 1989
  • 1989-01-28 EP EP19890101500 patent/EP0326979A3/fr not_active Withdrawn

Patent Citations (6)

Also Published As

Similar Documents

Legal Events